Deflector of a micro-column electron beam apparatus and method for fabricating the same

ABSTRACT

The present invention relates to a deflector of a micro-column electron beam apparatus and method for fabricating the same, which forms a seed metal layer and a mask layer on both sides of a substrate, and exposes some of the seed metal layer on which deflecting plates, wirings and pads are to be formed by lithography process using a predetermined mask. The wirings and pads are formed by plating metal on the exposed portion, and some of the metal layer is also exposed on which the deflecting plates are to be formed using a predetermined mask, and then the metal is plated with desired thickness, thereby the deflecting plates are completed. Therefore, by forming plurality of deflecting plates on both sides of the substrate at the same time through plating process, alignment between the deflecting plates formed on both sides of the substrate can be exactly made, and by fabricating a deflector integrated with the substrate and deflecting plates in a batch process, productivity and reproducibility is improved. In addition, since the deflecting plates, wirings and pads are directly formed on the substrate, structural safety is improved and thereby durability is also improved.

This is a divisional application of prior application Ser. No.10/617,703 filed on Jul. 14, 2003 now U.S. Pat. No. 6,797,963.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a deflector positioned between electronbeam lens in a micro-column electron beam apparatus used for exposureprocess for patterning a photoresist film, and more specifically to adeflector having a plurality of deflecting plates correspondinglyarranged at the upper and lower sides thereof and method for fabricatingthe same.

2. Description of the Prior Art

In general, a micro-column electron beam apparatus is used in anexposure process for patterning a photoresist film. In the micro-columnelectron beam apparatus, the photoresist film is exposed to a designedform by electron beam emitted from a cathode. The micro-column electronbeam apparatus consists of electron beam lens through which the electronbeam passes, and a deflector that electrically controls direction of theelectron beam and positioned between the electron beam lenses. Themicro-column electron beam apparatus receives data of a designed formfrom a pattern generator, and irradiates the electron beam to aphotoresist film formed on a mask or wafer with a direction commanded bythe data. Thereby, the photoresist film is exposed to the designed form.

The deflector has pairs of 2˜16 deflecting plates arranged opposite toeach other at the upper and lower sides of the deflector. The deflectingplates control the path of the electron beam in accordance with the datasupplied from the pattern generator.

In fabrication process of the deflector, the deflecting plates are madeby a wet etching or Deep RIE (reactive ion etch) process of a siliconwafer having a thickness of 0.2 mm to 1 mm, and anodic bonded on bothsides of a base isolation plate consisted of Pyrex Glass, etc. However,as this conventional method has to make deflecting plates and fix themon both sides of the base isolation plate, alignment and uniformitybetween the deflecting plates cannot be easily improved, andreproducibility and structural durability cannot also be improved.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention is to provide adeflector of a micro-column electron beam apparatus capable ofeliminating above mentioned disadvantages by forming simultaneouslyplurality of deflecting plates at the upper and lower sides of the baseisolation plate though metal plating process, and method for fabricatingthe same.

To achieve the above object, the deflector of a micro-column electronbeam apparatus in accordance with the present invention comprises anisolation substrate having a hole formed at center of the isolationsubstrate; plurality of deflecting plates formed along circumference ofthe hole at upper and lower sides of the isolation substrate; pluralityof pads formed on edges of the upper and lower sides of the isolationsubstrate; and plurality of wirings for connecting each of thedeflecting plates and each of the pads, wherein the deflecting plates,wirings, and pads are formed integrated.

A hole through which electron beams pass is formed within the hole byarrangement of deflecting plates, and the deflecting plates are arrangedopposite to each other with the isolation substrate.

The isolation substrate is made of ceramic alumina, and the deflectingplates, wirings, and pads are made of beryllium, phosphor bronze,bronze, cupro-nickel, stainless steel, or nickel, and formed by platingprocess.

In addition, a method for fabricating a deflector of a micro-columnelectron beam apparatus in accordance with the present inventioncomprises a step of burying and hardening polymer in a hole formed atcenter of a substrate; a step of forming first mask pattern so that someportion of seed metal layers is exposed to form deflecting plates,wirings and pads after forming the seed metal layers on both surfaces ofthe substrate; a step of forming first metal layers on the exposedportion of the seed metal layers; a step of forming second mask patternon both surfaces of the substrate to expose the first metal layers inwhich the deflecting plates are to be formed; a step of forming secondmetal layers on the exposed portion of the first metal layers; a step ofremoving the first and second mask patterns; and a step of removing theseed metal layers exposed and polymers buried in the hole.

The first mask pattern is a photoresist film, and formed by coating orlaminating process, and the first and second metal layers are made ofberyllium, phosphor bronze, bronze, cupro-nickel, stainless steel, ornickel, and formed by plating process.

The second mask pattern consists of polymers, and formed by laminatingprocess.

The step for removing polymers buried in the hole further comprises astep for plating metal on exposed surfaces of the first and second metallayers.

Although the present invention has been described in conjunction withthe preferred embodiment, the present invention is not limited to theembodiments, and it will be apparent to those skilled in the art thatthe present invention can be modified in variation within the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, effects, features and advantages of thepresent invention will become more apparent by describing in detail thepreferred embodiment of the present invention with reference to theattached drawings in which:

FIG. 1 shows a plane view for explaining a deflector of a micro-columnelectron beam apparatus in accordance with an embodiment of the presentinvention;

FIG. 2 shows a cross sectional view taken along the A1–A2 line of FIG.1;

FIG. 3 shows a perspective view for explaining a deflector of amicro-column electron beam apparatus in accordance with an embodiment ofthe present invention;

FIG. 4 shows a cross sectional view taken along the line B1–B2 of FIG.3;

FIG. 5A to 5M show cross sectional views for explaining method forfabricating the deflector of the micro-column electron beam apparatus inaccordance with the present invention;

FIG. 6 shows a plane view of a mask for explaining FIG. 5E; and

FIG. 7 shows a plane view of a mask for explaining FIG. 5H.

Similar reference characters refer to similar parts in the several viewsof the drawings.

DESCRIPTION OF THE PREPERRED EMBODIMENT

Silicon is used as a conductive material and Pyrex is used as a baseisolation plate in prior art. However, metals such as beryllium,phosphor bronze, stain, nickel etc. are used as the conductive materialin the present invention, and ceramic alumina as the base isolationplate, and deflecting plates of conductive materials are fabricatedusing plating process. Bronze is used as a representative metal forexplaining the present invention, however, it should be understand thatany metal that confirm to the purpose of the present invention can beused.

Hereinafter, embodiments of the present invention will be explained withreference to the accompanying drawings. In an embodiment of the presentinvention, eight deflecting plates called octapole are formed on theupper and lower sides of the deflector, respectively, and the eightdeflecting plates are opposite to each other.

The deflector of the micro-column electron beam apparatus in accordancewith the present invention, for example, consists of an isolationsubstrate 1 in which a hole 2 with 2 mm to 3 mm caliber is formed in thecenter of the isolation substrate 1, and eight deflecting plates 3formed on upper and lower sides of the isolation substrate 1,respectively, and arranged along the circumference of the hole 2 asshown in FIG. 1. Upper deflecting plates 3 a and lower deflecting plates3 b are arranged opposite to each other with the isolation substrate 1as shown in FIG. 2, a hole 4 with 500 μm to 1 mm caliber is formedthrough which electron beams pass within the hole 2 by the arrangementof the deflecting plates 3. In addition, pads 6 are formed at both edgesof the isolation substrate 1, and connected to each of the deflectingplates 3 through wirings 5.

FIG. 3 shows a perspective view for explaining the deflector as shown inFIG. 1, and FIG. 4 shows a cross sectional view taken along the lineB1–B2 of FIG. 3.

A method for fabricating deflector of a micro-column electron beamapparatus in accordance with the present invention will be describedbelow.

Referring to FIG. 5A, a hole 12 with 2 mm to 3 mm caliber is formed atthe center of the rectangular isolation substrate 11 made of ceramicalumina with 500 μm in thickness.

Referring to FIG. 5B, polymer 13 in kneading condition is buried to thehole 12 and hardened, and the polymer 13 on both surfaces of theisolation substrate 11 is polished so that those surfaces areplanarized.

Referring to FIG. 5C, seed metal layers 14 a and 14 b are vacuumdeposited on both surfaces of the isolation substrate 11.

Referring to FIG. 5D, photoresist films 15 a and 15 b are formed on eachof seed metal layers 14 a and 14 b. The photoresist films 15 a and 15 bare formed by coating or laminating of the photoresist materials.

Referring to FIG. 5E, the photoresist films 15 a and 15 b are patternedthrough exposing and developing processes using mask 60 formed withdeflecting plate pattern 61, pad pattern 62, and wiring pattern 63 asshown in FIG. 6, and some of the seed metal layers 14 a and 14 b areexposed to form the deflecting plate, pad and wiring.

Referring to FIG. 5F, metal layers 16 a and 16 b with 2 μm to 35 μm inthickness are formed on exposed portion of the seed metal layers 14 aand 14 b by a plating process. The metal layers 16 a and 16 bcorresponding to the pad pattern 62 and wiring pattern 63 are used tothe wiring 5 and the pad 6 shown in FIG. 1. At this time, heights of themetal layers 16 a and 16 b should be the same as those of thephotoresist films 15 a and 15 b, and the metal used for the plating isberyllium, phosphor bronze, bronze, cupro-nickel, stainless steel,nickel, etc.

Referring to FIG. 5G, polymer layers 17 a and 17 b with 200 μm to 500 μmin thickness are formed on all surfaces of the isolation substrate 11 bya laminating process. The thickness of the polymer layers 17 a and 17 bare adjusted in consideration of the thickness of the deflecting plate.

Referring to FIG. 5H, the polymer layers 17 a and 17 b are patternedthrough photography and etching processes using mask 70 formed withdeflecting pattern 71 as shown in FIG. 7, and some portions of the metallayers 16 a and 16 b is exposed to form the deflecting plates. Theetching process for patterning the polymer layers 17 a and 17 b isperformed with Deep RIE (Reactive Ion etch).

Referring to FIG. 5I, metal layers 18 a and 18 b with 200 μm to 500 μmin thickness are formed on exposed portion of the metal layers 16 a and16 b by a plating process. The deflecting plates 3 as shown in FIG. 1are completed by, stacked metal layers 16 a and 16 b and metal layers 18a and 18 b. At this time, heights of the metal layers 18 a and 18 bshould be the same as those of the polymer layers 17 a and 17 b to havea required thickness of the deflecting plate, and the metal used for theplating is beryllium, phosphor bronze, bronze, cupro-nickel, stainlesssteel, nickel, etc.

Referring to FIG. 5J, the polymer layers 17 a and 17 b and thephotoresist films 15 a and 15 b are removed by using solvent.

Referring to FIG. 5K, exposed portion of the seed metal layers 14 a and14 b are removed.

Referring to FIG. 5L, a hole 19 is formed through which the electronbeams pass by oxidizing polymers 13 to be removed at about 500° C.buried in the hole 12 of the isolation substrate 11.

Referring to FIG. 5M, metal (Au; 22 a and 22 b) is plated on exposedsurfaces of upper and lower deflecting plates 20 a and 20 b stacked withmetal layers 16 a and 16 b and metal layers 18 a and 18 b, upper andlower wirings and pads 21 a and 21 b consisted of seed metal layers 14 aand 14 b and metal layers 16 a and 16 b. The metal is plated inthickness of 0.1 μm to 0.5 μm.

A deflector having eight deflecting plates respectively formed on theupper and lower sides of the substrate has been described in the presentinvention, however, the deflector having deflecting plates formed onlyat the upper or lower side of the substrate can also be fabricated.

As mentioned above, the present invention exposes some portion of theseed metal layers in which deflecting plates, wirings, and pads are tobe formed by photolithography process using a predetermined mask, afterforming seed metal layers on both surfaces of a substrate. Wirings andpads are formed by plating metal on the exposed portion, and someportion in which the deflecting plates are to be formed by lithographyprocess using a predetermined mask is exposed, and then the deflectingplates are formed by plating metal with required thickness.

Since plurality of deflecting plates are formed on both sides of thesubstrate through metal plating at the same time, alignment betweenthose deflecting plates and corresponding relation between thosedeflecting plates on upper and lower part of the substrate is madeexact, and productivity and reproducibility is improved by fabricatingthe deflector integrated with the substrate and deflecting plates.

Furthermore, since the deflecting plates, wirings and pads are directlyformed on the substrate, structural safety is improved and therebydurability is also improved.

In addition, the present invention forms the polymer layers used as amask layer by laminating process when performing metal plating, thepolymers can be easily formed and removed, shape (rectangular degree)and size of side wall of the deflecting plate can be exactly controlled,and alumina substrate having high intensity is used for the substrate,and the deflector is fabricated by metal plating process, so thatstacking and packaging is facilitated and multi layered deflectors canbe fabricated.

Although the present invention has been described in conjunction withthe preferred embodiment, the present invention is not limited to theembodiments, and it will be apparent to those skilled in the art thatthe present invention can be modified in variation within the scope ofthe invention.

1. A method for fabricating a deflector of a micro-column electron beamapparatus, comprising the steps of: (a) burying and hardening polymer ina hole formed at center of a substrate; (b) forming first mask patternso that some portion of seed metal layers is exposed to form deflectingplates, wirings and pads after forming said seed metal layers on bothsurfaces of said substrate; (c) forming first metal layers on theexposed portion of said seed metal layers; (d) forming second maskpattern on both surfaces of said substrate to expose said first metallayers in which said deflecting plates are to be formed; (e) formingsecond metal layers on the exposed portion of said first metal layers;(f) removing said first and second mask patterns; and (g) removing saidseed metal layers exposed and polymers buried in said hole.
 2. Themethod as claimed in claim 1, further comprising: a step for planarizingsaid polymers on both surfaces of said substrate by polishing processafter said step (a).
 3. The method as claimed in claim 1, wherein saidfirst mask pattern is a photoresist film, and formed by coating orlaminating process.
 4. The method as claimed in claim 1, wherein saidfirst and second metal layers are made of beryllium, phosphor bronze,bronze, cupro-nickel, stainless steel, or nickel, and formed by platingprocess.
 5. The method as claimed in claim 1, wherein said second maskpattern is made of polymers, and formed by laminating process.
 6. Themethod as claimed in claim 1, further comprising: a step for platingmetal on exposed surfaces of said first and second metal layers aftersaid step (g).
 7. The method as claimed in claim 6, wherein said metalis gold.